Airbag coating

Abstract

Coating compositions, which are used as a monolithic coating layer for airbags. The coating compositions include a combination of urethanes which are blended together. At least one of the urethane components provides gas-retaining properties and the other provides the aging stability. The gas-retaining urethane may be characterized as having high tensile strength at break, high elongation at break, and a 100% modulus less than 1,200 psi. The aging stability urethane has a polycarbonate backbone as result of a manufacturing process in which a polycarbonate diol is reacted with an isocyanate. The resulting coating compositions, when applied as a single layer to an airbag fabric, result in an airbag with good gas retention and aging stability.

1. An airbag fabric having a monolithic coating layer applied to at least a portion thereof, said monolithic coating layer comprising a blend of (a) a gas-retaining urethane characterized by a tensile strength at break of at least 2,500 psi, and a 100% modulus of less than about 1,200 psi; and (b) an aging stability urethane characterized by a 100% modulus of less than about 800 psi and having a 100% polycarbonate polymer backbone. 
     
     
       2. The airbag fabric of  claim 1 , wherein said gas-retaining urethane is synthesized using a polyol selected from the group consisting of polycarbonate polyols, polyether polyols, silicon-based diols, polyester diols, and combinations thereof. 
     
     
       3. The airbag fabric of  claim 2 , wherein said gas-retaining urethane is synthesized using at least two polyols. 
     
     
       4. The airbag fabric of  claim 1 , wherein said aging stability urethane is synthesized using a polycarbonate polyol. 
     
     
       5. The airbag fabric of  claim 1 , wherein said monolithic coating layer further comprises at least one additive selected from the group consisting of flame retardants, thickeners, rheology modifiers, anti-blocking agents, colorants, de-foamers, pigments, heat stabilizers, UV stabilizers, antioxidants, cross-linking agents, adhesion promoters, fillers, plasticizers and synergists. 
     
     
       6. The airbag fabric of  claim 1 , wherein the dry add-on weight of said monolithic coating layer is from about 0.5 oz/yd 2  to about 1.5 oz/yd 2 . 
     
     
       7. The airbag fabric of  claim 1 , wherein the dry add-on weight of said monolithic coating layer is from about 0.5 oz/yd 2  to about 1.0 oz/yd 2 . 
     
     
       8. The airbag fabric of  claim 1 , wherein the dry add-on weight of said monolithic coating layer is from about 0.5 oz/yd 2  to about 0.6 oz/yd 2 . 
     
     
       9. The airbag fabric of  claim 1 , wherein the dry parts ratio of (a) to (b) is about 80:20. 
     
     
       10. The airbag fabric of  claim 1 , wherein the dry parts ratio of (a) to (b) is about 50:50. 
     
     
       11. The airbag fabric of  claim 1 , wherein the dry parts ratio of (a) to (b) is about 63:37. 
     
     
       12. The airbag fabric of  claim 1  is a One Piece Woven Airbag. 
     
     
       13. The airbag fabric of  claim 1  is a single layer fabric. 
     
     
       14. The airbag of  claim 1 , wherein the airbag is made from synthetic yarn.